1. Field of the Invention
The present invention relates to a metamaterial, which is an artificial material or medium for propagating an electromagnetic wave, and relates, in particular, to a metamaterial, which functions as an electromagnetic wave propagation medium, and in which only the magnetic permeability of the equivalent dielectric constant and the magnetic permeability of the material or medium becomes negative.
2. Description of the Related Art
Materials having properties that are not existing in the nature can be artificially configured by arraying small pieces of metal, dielectric, magnetic material, a superconductor or the like (unit structure) at intervals sufficiently smaller than the wavelength (equal to or smaller than about one-tenth of the wavelength). The materials are called metamaterials in the sense of materials that belong to a category larger than the category of the material existing in the nature (See, for example, the Patent Documents 1 to 3). The properties of the metamaterials variously change depending on the shape and the material of unit structures and the array of them.
Among others, metamaterials whose equivalent dielectric constant ∈ and the magnetic permeability μ simultaneously became negative were named the “Left-Handed Materials (LHM)” since the electric field, the magnetic field and the wave number vector thereof configure the left-handed system. The left-handed materials are referred to as the left-handed metamaterials in the present specification. In contrast to this, the ordinary materials whose equivalent dielectric constant ∈ and the magnetic permeability μ simultaneously become positive are called the “Right-Handed Materials (RHM)”.
A “negative refractive index material” having a negative refractive index is currently proposed by using the concept of the aforementioned “metamaterial”. By using the negative refractive index owned by the negative refractive index material and the properties of an increase in the evanescent wave, the possibility of the achievement of a super lens, whose resolution performance exceeds a diffraction limit which is a physical limit, has been theoretically indicated (See, for example, the Non-Patent Document 1).
Moreover, in order to achieve the negative refractive index material, a “left-handed material” in which the effective dielectric constant and the magnetic permeability both become negative has been proposed. This is an array of wire resonators for making the dielectric constant negative and split ring resonators (SRR) for making the magnetic permeability negative, and its negative refractive index operation is indicated (See, for example, the Non-Patent Document 2).
Prior Art Documents related to the present invention are as follows: